Electric fuse



Patented Aug. 18, 1931 UNITED STATES PATENT orrics f o nt I-I. HICKEY, or SAN FRANCISCO, CALIFORNIA, ASSIGNOR T HICKEY rose a Menurnorunrne COMPANY, or SAN rnanorsoo; car ronum, A CORPORATION 1 or GALIFOBNiA' anaemic FUSE Application filed May a, 19w. Serial No. 188,735.

My invention'relates to improvements in fuse construction for refillable electric fuses and the like whereby an extremely strong andrugged fuse is obtained which will withstand theshock of blowing in high power electriccircuits without injury to the fuse and without endangering surrounding obj sets, and in'which the fusible element is readily replaceable when a fuse is blown.

The primar object of the present invention is to provide an improved fuse construction which willpermit the slow escape of gas from the fuse when blown without'damage to the fuse or to surrounding objects.

, Another important object is to provide an improved construction which will be extremely strong and which will effectively seal the fuse except for a' valvulated vent.

A further object is to provide an improved fuse construction which will facilitate the assembly ofthe fuse and the replacement of fusible elements when the fuse is blown.

I accomplish these and other objects by means of the improved device disclosed in the drawings forming a part of the present applicationwherein like characters of reference are used to designate similar parts throughout the specification and drawings,

and in which, 7'

side elevation of my improved outer casshow the fuse construction, a portion of the ing section being broken away to vent passage.

' Fig. 2 is alongitudinal section of the fuse taken at right angles to the position shown in Fi 1. I

Fig. 3 is a side elevation of the counductor assembly showing the manner in which the fusible element is connected therebtween.

Fig. 4 is a front elevation of the separable conductor blade.

' i Fig. 5 is an enlarged broken sectional detail showing the manner in which the vent passage is formed.

Referring to the drawings, my improved fuse consists of a casing formed from inner and outertubular casing sections 1 and 2, the

inner casing section being telescoped within the outersection and forming a close sliding fit therein. A conductor member compris within the casing ing a blade 3, an annular flange portion 1, and an inward extension 6 formed integrally with the blade and flange, is detachably secured upon one end of the casing by means of a collar 7 threaded onto the end of the inner casing section 1. The flange portion 4 is shouldered as at 5 and isheld seated upon the end of the casing section 1 and effectually closes the end of the casing.

. A second conductor member is detachably and to be detachably clamped onto the blade 9 by means of a suitable clamping member 14L held by screws 16 threaded into an enlarged portion 17 of the blade. The extension portion 12 is provided with an annular flange 18 arranged to abut against the inner surface of the flange 11, and fitting loosely in the Casing. g

A fusible conductor 19 of calculated current carrying capacity is detachably con nected between the extensions 6 and 12 by means of bolts or other suitable securing elements 21. The conductor members are held against turning and positioned in proper alinement by means of lugs 22 engaging notches 23 formed upon the ends of the casing section 1.

A vent passage 24 is formed at each end to permit the slow escape of gas when the fuse is blown, said passage being formed preferably as a spiral groove forming a continuation of the threads upon which the collars 7 and 8 arethreaded, said grooves continuing inwardly a substantial distance toward the middle of the casing. Openings 26 are formed through the inner casing section 1 to communicate between the interiorof the casing and the inner end of is blown. The spiral formed as a tapered groove such as a pipe thread whereby a passage of an area gradually increasing toward the ends of the easing is produced, said gradually increasing area. serving to permit a gradual expansion of the escaping gas before issuing from the end of the passage.

In the form of fuse illustrated in the drawings, the outer casing member 2 is made rotatable upon the inner casing section 1, and is provided with openings 27 arranged to be moved to register with the openings 26 in the inner casing section whereby the fusible element may be observed for purposes of inspection and the like. The outer casing member is normally held in closed position by means of suitable springs 28 mounted at the ends of the. casing and being secured at one end to pins 29 carried by the casing member 2 and at the opposite end to pins 31 secured to the inner casing member 1, said pins 31 being received within notches 32 formed in the ends of the casing member 2 and limiting the movement of the outer casing member. In closed position, the openings 26 and 27 are circumferentially spaced a substantial distance so as to prevent leakage between the casing members and the direct escape of gas through said openings. A groove 33 is formed in the surface of the inner casing member 1 to communicate between each open ing 26 and a passage 24: whereby the gas may pass through the openings 26 and grooves 33 to the vent passages.

If it is not desired to render the fusible element observable, the casing members 1 and 2 may be permanently assembled, in this case, the groove 2% is cut and small holes 26 are drilled to communicate between the interior of the casing and the vent aassage formed by passage is preferably said groove.

In operation, a fusible conductor 19 of the desired current carrying capacity is secured between the extensions 6 and 12, as shown in Fig. 3 of the drawings, the assembled parts then being inserted into the casing and the collar 7 applied to secure the flange 4 against the end of the casing. IVhen thus assembled onto the casing. the lug 13 extends outward- 1y from the casing. The blade 9 is then ap plied over the lug and the flange 11 moved against the end of the casing and secured by the collar 8, the clamping member 14 being then clamped against the lug 13 to insure a perfect electrical connection between the blade portion and the extension 12. As thus assembled. the fuse is applied upon an ordinary fuse block and operates in the ordinary manner.

In case the fuse blows, the sudden expansion caused within the casing is relieved through the vent 2%. The highly heated gases from the casing are conducted through the tortuous passage and permitted to gradually expand so that when the gases issue from the end of the threads at the ends of the casing the temperature will have been reduced sufliciently to avoid any injury to surrounding objects. The casing members 1 and 2 are made to fit so closely that gas can not escape between said members except along the spiral passage. The flanges 4 and 11 form plates closing the ends of the casing and carrying the pressure due to the blowing of the fuse, any possible leakage around the edges ofthe flanges being directed through the threads by which the collars 7 and 8 are secured to the casing and there by retarding the escape of gas sufficiently to avoid causing lire or other damage.

To replace a blown fusible element 19, the screws 16 are loosened and the collars 7 and 8 removed from the ends of the casing to permit the conductor members to be sepa rated from the casing. A fresh fusible elc ment is then secured between the conductor members and the several parts re-asselnbled and secured upon the casing as above described.

iVhilc I have illustrated and described what I now con ider to be the preferred eon- "tion of my invention, the device is of c subect to mrulitication in various de ti Jithout departing from the spirit of the invention. I. therefore, do not wish to cstrict myself to the specific details of construction illustrated and described, but desire to rail myself of all modifications which may fall within the scope of the appended claims.

Having thus described my invention what I claim as new and desire to secure by Letters Patent is,

1. An electric fuse connprisin a casing formed from a pair of telescoping tubular sections; a fusible element mounted within the casing; and a tortuous groove formed upon one casing section and communicating with the interior of the casing through an opening formed in the inner casing section to provide a vent between the casings for the escape of gas when the fuse is blown.

2. An electric fuse comprising a casing formed from a pair of telescoping tubular sections; a fusible element mounted within the casing; and a spiral groove formed upon one of the tubular sections adjacent each end thereof to form passage between the casing sections, said passages con'nnunicating with the interior of the casing through openings formed in the inner casing section to provide vents for the escape of gas when the fuse is blown.

3. An electric fuse comprising a casing formed from a pair of telescoping tubular sections; a fusible element mounted within the casing; a spiral thread formed upon the ends of the inner section to form a passage between the casing sections, said passages casing section to provide vents opening outwardly at the ends of the casing for the escape of gas when the fuse is blown.

4:- An electric fuse comprising a casing formed from a pair of telescoping tubular sections; a fusibleelement mounted within the casing; a tapered spiral thread formed upon the ends of the inner section to form a passage between the casing sections, said passages connnunicating with the interior of the casing through openings formed in the inner casingsection to provide vents of gradually increasing size communicating between openings formed through the inner casing section and the end of the casing.

5. An electric fuse comprising a casing formed from a pair. of telescoping tubular sections; conductors detachably mounted upon the ends of the casing; a fusible element within the casing detachably connected between the conductors; and spiral passages formed between the tubular sections and communicating between openings formed in the inner section and the ends of the casing to provide vents for the escape of gas from the casing when the fuse is blown.

6. An electric fuse comprising a casing; a conductor comprising a blade provided with a flange, arranged to abut against one end of the casing and an inwardly disposed extension formed integral with the blade and flange; a second conductor comprising a blade provided with a flange arranged to abut against the opposite end of the casing and having an axial recess; a conductor extension having a flange arranged to abut against the inner surface of the second conductor flange and provided with a shank extending axially into the recess; a clamping block mounted in connection with the blade and engaging the shank for detachably clamping the conductor extension in engagement with the second conductor; a fusible element detachably connected between the inward extensions of the conductors; and means for detachably securing the conductors upon the ends of the casing.

7. An electric fuse comprising a casing; a conductor comprising a blade provided with a flange, arranged to abut against one end of the casing, and an inwardly disposed extension formed integrally with the blade and flange; a second conductor comprising a blade provided with a flange arranged to abut against the opposite end of the casing and having an axial recess; a conductor extension having a flange arranged to abut against the inner surface of the second conductor flange and provided with a shank extending axially into the recess; a clamping block mounted upon the blade and recessed to engage the shank for detachably clamping the conductor extension in engagement with the second conductor; fusible element detachably connected between the inward extensions of the conductors; collars threaded onto the ends of the casing for detachably securing the conductors upon the ends of the casing; and a vent passage'formed within the body of the casing to permit the escape of gas when the fuse is blown.

8. An electric fuse comprising a casing; a conductor. comprising ablade provided with a flange, arranged to abut against one end of the casing, and an inwardly disposed extension formed integrally" with the blade and flange; a second conductor comprising a blade provided with a flange arranged to abut against the opposite end of the casing; a conductor extension having a flange arranged to abut against the inner surface of the second conductor flange; means fordetachably clamping the conductor extension in engagement with the second conductor; a fusible element detachably connected be tween the inward extensions of the conductors; and collars threaded onto the ends of the casing for detachably securing the conductors upon the ends of the casing; and a tortuous passage formed within the body of i the casing at each end thereof and communicating with the interior of the casing to permit the slow escape of gas when the fuse is blown.

9. An electric fuse comprising a casing formed from a pair of telescoping tubular sections; a conductor comprising a blade provided with a flange, arranged to abut against one end of the casing, and an inwardly disposed extension formed integrally with the blade and flange; a second conductor comprising a blade provided with a flange arranged to abut against the opposite end of the casing; a conductor extension having a flange arranged to abut against the inner surface of the second conductor flange; means for detachably clamping the conductor extension in engagement with the second conductor; a fusible element detachably connected between the inward extension of the conductors; collars threaded onto the ends of the casing for detachably securing the conductors upon the ends of the casing; and grooves formed in the inner casing section and communicating between openings formed in the inner casing section and the cap engaging threads to form a vent passage to permit the slow escape of gas from the casing when the fuse is blown.

In witness whereof I hereunto set my signature.

JOHN H. HIGKEY. 

